Objective To evaluate the association between maternal prenatal exposure to polycyclic aromatic hydrocarbons and newborns' DNA telomere length in cord blood lymphocytes.
Methods A total of 347 pregnant women were recruited from two hospitals in Taiyuan and provided written informed content. Their urinary samples were collected a week before delivery and were stored at -80℃. Newborns' cord blood samples were collected at delivery to extract DNA from lymphocytes. Mothers' urinary concentrations of four PAH metabolites, including 2-hydroxynaphthalene (2-OH NAP), 2-hydroxyfluorene (2-OH FLU), 9-hydroxyphenanthrene (9-OH PHE), and 1-hydroxypyrene (1-OH PYR), were detected by high performance liquid chromatography. DNA telomere lengths in cord blood lymphocytes of newborns were measured by real-time fluorescence quantitative PCR. Univariate analysis on telomere length included one-way ANOVA, t' test, and Spearman correlation analysis; analysis of covariance was used to assess the dose-response association between PAH metabolites and telomere length; multiple linear regression analysis was used to evaluate the association between four maternal urinary PAH metabolites and newborns' DNA telomere length in cord blood lymphocytes.
Results The median concentrations of 2-OH NAP, 2-OH FLU, 9-OH PHE, and 1-OH PYR in the mothers' urine samples were 7.56, 3.89, 3.42, and 1.55 μg/g (adjusted for creatinine), respectively. The median (P25-P75) of relative DNA telomere length in the newborns' cord blood lymphocytes was 0.85 (0.61-1.31). With 2-OH FLU and 1-OH PYR concentrations increasing in mothers' urine samples, newborns' DNA telomere length in cord blood lymphocytes showed decreasing trends (P=0.022, P=0.033). Each lnunit increase in urinary 2-OH FLU and 1-OH PYR was associated with 12.19% and 8.16% decrease in DNA telomere length in cord blood lymphocytes after adjusting for potential confounders.
Conclusion Maternal PAHs exposures before delivery are associated with decreased newborns' DNA telomere length in cord blood lymphocytes.
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